cmd/compile: implement min/max builtins

cmd/compile: implement min/max builtins

Updates #59488.

Change-Id: I254da7cca071eeb5af2f8aecdcd9461703fe8677
Reviewed-on: https://go-review.googlesource.com/c/go/+/496257
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Auto-Submit: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Keith Randall <khr@google.com>